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Jobisdone [24]
3 years ago
14

Roy is twice as old as Joan, and in 3 years the sum of their ages will be 21 years. Find their present ages.

Mathematics
1 answer:
Lisa [10]3 years ago
8 0

Answer:

Roy is 10 years old at present and Joan is 5 years old at present

Step-by-step explanation:

Let

x----> Roy's age

y----> Joan's age

we know that

x=2y ----> equation A

(x+3)+(y+3)=21 ----> equation B

substitute equation A in equation B

(2y+3)+(y+3)=21

solve for y

3y+6=21

3y=21-6

3y=15

y=5 years

Find the value of x

x=2y  ----> x=2(5)=10 years

therefore

Roy is 10 years old at present

Joan is 5 years old at present

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Given the trinomial 2x2 − 5x + 3, what is the value of the Discriminant and what can be said about the solutions.
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3 years ago
The safety inspector in a large city wants to estimate the proportion of buildings in the city that are in violation of fire cod
storchak [24]

Answer:

Check Explanation.

Step-by-step explanation:

The sample will be a representative of the entire build us in the city.

For a sample size 35, 3 have fire code violations, hence, the proportion of houses with fire code violations = (3/35) = 0.0857 = 8.57 %

The uncertainty in the estimate is given in the form of standard error.

Standard error = √[(p(1-p)/n]

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Standard error of the sample = √(0.0857×0.9143/35) = 0.1616

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8 0
3 years ago
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Answer:

0.2637

Step-by-step explanation:

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3 years ago
5(10-6)<br> 6(4+10)<br> Help me, I find the bracket confusing
ira [324]

Answer:

20

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Step-by-step explanation:

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4 0
3 years ago
Read 2 more answers
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